“The fact is sterling is weaker, it’s more expensive to import goods… so we have to absorb that within our margin,” he said.

“I’m not going to get into some sort of ding-dong with the secretary of state.”

Dominic Raab told the BBC on Thursday it was a mistake for “business that aren’t doing so well to blame Brexit”.

“I don’t doubt that some of the uncertainty around these negotiations will have an impact on business – that’s why we are putting all our energy into getting the good deal we want with our EU friends and partners,” he said.

“All I am just gently saying is that it’s rather easy for a business to blame Brexit and the politicians rather than take responsibility for their own situation.”

Mr Raab’s comments appear to have been in response to Sir Charlie’s warning in John Lewis’s half-year results that “with the level of uncertainty facing consumers and the economy, in part due to ongoing Brexit negotiations, forecasting is particularly difficult”.

The owner of the John Lewis department store chain and Waitrose said it continued to expect annual profits to be “substantially lower than last year”.

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Mr Raab also said the government was preparing for a no-deal Brexit despite being confident that eventuality would not come to pass: “Getting a deal with the European Union is still by far and away the most likely outcome.”

Meanwhile, the Brexit secretary welcomed a promise by two mobile operators, Vodafone and Three, not to impose Europe roaming charges for UK customers if Britain leaves the bloc with no deal.

“What we have said is we would like to see other companies following suit, but, in any event, we would legislate for a limit on roaming charges to make sure in a no-deal scenario that we protect British consumers,” Mr Raab said.

A new raft of technical papers is being released by the government on Thursday outlining the impact of a no-deal Brexit on business and consumers.

Mr Raab also accused those warning about shortages of food and medicines after a no-deal withdrawal of “scaremongering”, saying it was “nonsense” to claim UK supermarkets would run out of food.